The invention relates to a feed device for a motor vehicle for feeding washer fluid from a reservoir to a washer jet arranged in front of a window or lens, having a feed pump which is driven by an electric motor and having a ventilating means for the electric motor. Furthermore, the invention relates to a reservoir for a feed device provided for feeding washer fluid to motor-vehicle washer jets arranged in front of a window or lens, the feed device having a feed pump which is driven by an electric motor and a housing having a ventilating device for the electric motor.
Feed devices of this type together with the associated reservoir are frequently used in motor vehicles today and are known from practice. The ventilating means generally has a recess which is arranged in the housing and through which air can flow into and out of the electric motor without hindrance. Since the reservoir for the washer fluid together with the feed devices arranged thereon is generally arranged at a very low point in the motor vehicle, during passage through water the feed devices are flooded by the water. In the process, water can penetrate through the ventilating means into the electric motor and can damage the latter. However, it is not expedient to completely seal the housing of the electric motor, since condensation water forming in the housing has to be removed. Otherwise, the electric motor becomes corroded by the condensation water.
The invention is based on the problem of designing a feed device of the type mentioned at the beginning in such a manner that it as reliably as possible prevents water from penetrating into the electric motor when the motor vehicle passes through water. Furthermore, a reservoir of the type mentioned at the beginning is to be designed in such a manner that it prevents water from penetrating into the electric motor.
According to the invention, the problem mentioned first is solved by means for forming an air bubble within the electric motor in the event of a water level reaching the electric motor in its designated installation position.
This design of the electric motor enables an air bubble to be trapped within the housing in the event of a high water level. This air bubble prevents water from penetrating into the housing and therefore prevents damage to the electric motor. At a low water level, the housing is ventilated via the ventilating device as in the case of the known feed device. The invention reliably protects the electric motor from corrosion not only when passing through water, but also during engine washing or during intense inspections of the protective system. Since passage of the motor vehicle through water is frequently restricted to a designated period of time, it is frequently sufficient to retard the penetration of water and therefore to ensure the formation of the air bubble for a designated period of time.
According to an advantageous development of the invention, the air bubble in the housing can be produced in a simple manner if the ventilating means has an opening which points downward in the designated installation position of the electric motor, and if the housing is designed such that it is hermetically sealed in the upper region. This enables air to be exchanged by the electric motor with the surroundings via the downwardly pointing opening. However, water cannot penetrate through the opening, since the air contained in the electric motor cannot escape.
According to another advantageous development of the invention, a further option for producing the air bubble resides in the fact that the opening can be closed by means of a valve and channels or gaps present in the remaining region of the housing do not exceed a designated cross section. By means of this design, complicated sealing of the upper region of the housing is not required, since water cannot penetrate into the electric motor, at least for a long period, via relatively small channels which are present, for example, in the case of multiwire electric lines or in the case of press fits. In the most favorable case, with the installation of an additional component the known feed device can thereby be sealed in a simple manner against water penetrating.
According to another advantageous development of the invention, the housing can be reliably sealed with a particularly low outlay if the lower edge of a cap arranged on the upper side of the electric motor is arranged level with the opening.
The feed device according to the invention can be manufactured particularly cost effectively if the cap forms a subregion of the opening.
The installation of the feed device according to the invention turns out to be particularly simple if the housing of the electric motor has a channel guided up to the opening.
According to another advantageous development of the invention, entry of spray water into the housing of the electric motor can be avoided in a simple manner if a recess is arranged in the housing of the electric motor on the opposite side of the opening and if the recess and the opening are connected to each other via the channel.
According to another advantageous development of the invention, an escape of air between the housing and the cap can be avoided in a simple manner if the cap is sealed with respect to the housing of the electric motor.
The feed devices are supplied with electric current via electric lines. In this case, it has been established that the air can escape from the housing through the strands of the electric lines, which strands comprise a plurality of individual wires. According to another advantageous development of the invention, an escape of air through the electric lines can be avoided in a simple manner if contacts which are arranged on the upper side of the electric motor and are provided for the connection of electric lines are sealed with respect to the cap or the housing. This prevents air from the electric motor from penetrating as far as the electric lines, with the result that the type of lines connected to the contacts is irrelevant to the sealing of the electric motor.
According to an advantageous development of the invention, the sealing of the contacts turns out to be particularly simple in structural terms if the cap has a seal manufactured from an elastomeric material, and if the seal bears tightly against the contacts. The seal preferably bears against the inside of the cap.
According to another advantageous development of the invention, a housing of the known feed device, which housing is sufficiently sealed in the upper region, can be sealed in a simple manner against water penetrating if the housing is connected in the region of its recess, which is provided for ventilation purposes, in a sealing manner to an elastic, annular element or partially annular element, and if the element has a channel with the opening.
According to another advantageous development of the invention, entry of spray water into the electric motor is further avoided if the annular element covers an annular groove arranged on the outside of the housing of the electric motor in the region of the recess provided for ventilating purposes, and if the channel is connected to the annular groove.
The channel could be guided in an angular manner around the feed pump. The manufacturing costs of the feed unit according to the invention are further reduced if the channel is inclined by a designated angle with respect to the axis of symmetry of the electric motor.
According to another advantageous development of the invention, the channel has sufficient intrinsic stability if it has an encircling collar at its free end.
According to another advantageous development of the invention, a particularly small structural outlay is required in order to avoid water from penetrating through the opening if a valve controlled by a float is arranged on the opening or in the channel connected to the opening.
According to another advantageous development of the invention, penetration of spray water through the opening into the electric motor can be avoided in a simple manner if the opening is arranged on a side of the electric motor that is to face the reservoir. The opening is thereby protected by the reservoir. If the float is arranged in the region of the opening, movement thereof by spray water is also prevented and if the reservoir is installed in the engine compartment of the motor vehicle, damage thereto, for example during engine washing, is prevented.
The feed device according to the invention turns out to be particularly compact if a housing of the feed pump to be arranged below the electric motor has a subregion of the channel guided to the opening.
According to another advantageous development of the invention, the valve turns out to be particularly simple in terms of structure if a valve body of the valve which is designed as a float is mounted pivotably.
The problem mentioned second, namely the provision of a reservoir of the type mentioned at the beginning for preventing water from penetrating into the electric motor is solved according to the invention in that the reservoir has an edge which fits over the electric motor and is guided at least to the lower side of the housing. By means of this design, the air bubble protecting the electric motor from water penetrating is produced by the reservoir. This design does not therefore require any change to the structure of the electric motor.